CLINICAL PAIN STUDIES: 1. Clinic records of 25 methadone patients hospitalized on surgical or trauma services and given analgesics will be compared with a control group (50) of non-hospitalized methadone patients to determine differences in methadone maintenance dosages. 2. Methadone clinic patients hospitalized on surgical services and requiring analgesics over and above their methadone will, in a double-blind, single random presentation trial, receive either placebo (25 subjects) or 100 mgm. indomethacin (25 subjects) and monitored for relief of pain. 3. An oral quantal-bioassay single dose, double-blind trial of varying mixtures of codeine and caffeine compared with doses of each drug alone in post-surgical in-patients for analgesia. 360 patients will be studied and interaction will be looked for using specially devised statistical methods. EXPERIMENTAL PAIN STUDIES: Cutaneous electrical stimulation, cold pressor & electrical intramuscular stimulation will be used in 72 healthy paid volunteers to test the analgesic response of graded doses of oral codeine, meperidine, aspirin and d-propoxyphene.